ES2325999T3 - DOUBLE FACE SELF-ADHESIVE TAPES WITH REFLECTOR AND ABSORBENT PROPERTIES OF THE LIGHT TO PREPARE LIQUID GLASS SCREENS. - Google Patents

Abstract

Special self-adhesive tape to adhere optical indicators of liquid crystal data (LCDs), which has an upper face and a lower face, with photoreflective properties on the upper face and photoabsorbent on the lower face, and also a support sheet with an upper face and a lower face, the self-adhesive tape being provided on both sides of an external self-adhesive layer, characterized in that - the support sheet is transparent, - at least one self-adhesive layer dyed black is provided, to absorb light, between the external self-adhesive layers, - at least the outer self-adhesive layer of the upper face is transparent, and - at least two reflective metal layers are provided, one between the support sheet and the self-adhesive layer of the upper face, and another between the support sheet and the tinted self-adhesive layer of black

Description

Self-adhesive double-sided tapes with reflective and light absorbing properties to make liquid crystal displays

The present invention relates to tapes double-sided self-adhesive with several support layers, several layers self-adhesive, and reflective and light absorbing properties, for making liquid crystal displays (glass displays liquid, LCDs).

In the era of industrialization tapes Self-adhesive are widely disseminated process materials. In the specific case of his employment in the manufacture of computers must meet very high requirements. Apart from a low tendency to gas evolution self-adhesive tapes have to be Usable within a wide range of temperatures and should satisfy certain optical properties.

An application sector is made up of optical data indicators, of liquid crystal (screens or liquid crystal displays, LCDs), necessary for computers, TVs, laptops, PDAs, mobile phones, digital cameras, etc. Fig. 1 shows the scheme of a double-sided adhesive tape, with a black layer for absorption and a layer for reflection, according to the technical state, where:

one

LCD glass

2

black double-sided adhesive tape and white

3

self-adhesive dough

4

light source (LED)

5

light rays

6

double sided adhesive tape

7

light conductor

8

reflective sheet

9

LCD housing

10

black absorbent tape face adhesive

eleven

reflective face

12

visible area

13

"blind" zone

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To manufacture liquid crystal displays adhere LEDs (LED, light emitting diode) - as a source of light- with the LCD module. For this, tapes are generally used double-sided self-adhesive The black pigmentation serves so that in the area of the double-sided self-adhesive tape does not pass light from within out and vice versa.

There are many ideas to achieve this type of black coloration On the other hand you want to increase efficiency light from the back of the light module and therefore it preferably use double-sided adhesive tapes that are black on the one hand (light absorber) and reflect the light on the other.

To make the black face there are many concepts.

A concept for making black ribbons double-sided self-adhesive consists of dyeing the support material. In the electronics industry, tapes are most preferably used double-sided self-adhesive with polyester film holders (PET), because they are cut very well. PET brackets are also they can dye with carbon black or black pigments, to get light absorption The disadvantage of this current method is the Low light absorption In very thin support layers you can only incorporate a relatively small amount of particles of carbon black, or other black pigment, and therefore is not achieved a complete absorption of light. Both visually and with sources of more intense light (intensity greater than 600 Candles) can be appreciate the lack of absorption.

Another concept for tape making black double-sided self-adhesive consists of producing by coextrusion a bilayer support material. The support sheets are normally manufactured by extrusion. By coextrusion, next to usual support material is extruded a second black layer that It plays the role of light absorber. This method too It has several drawbacks. For example, for extrusion should be used non-stick agents, which then form in the product the called needle points. These needle points are defects optical (light passes through these pores) and undermine the LCD operation.

Layer thicknesses are another problem, since first the two layers are individually shaped in the nozzle and in this way only relatively support layers can be obtained thick, which makes the sheet inflexible and adapts poorly to the surfaces where it should adhere. On the other hand the black cape it has to be quite thick, otherwise it can't achieve total absorption. Another disadvantage is the alteration of the mechanical properties of the support material, because those of the black layer differ from those of the initial support material (eg PET pure). Another disadvantage of the bilayer version of the support material is the different anchorage of the adhesive mass to the support material coextruded In this embodiment the double adhesive tape layer always has a weak point.

Another idea is to apply a layer of black paint on the support material, which can be done on one or both sides of the support material. But this concept It also has some disadvantages. On the one hand, in this case defects also appear easily (needle points) caused by the non-stick agent incorporated during sheet extrusion process. These defects are unacceptable. For final use on the liquid crystal display. On the other hand its maximum absorption capacity does not meet the requirements, since that only relatively thin layers of paint can be applied. In this case the layer thicknesses also have a limit superior, if not, the mechanical properties of the material would vary support.

The development of glass screens Liquid follows a trend. On the one hand the glass screens liquid will be lighter and flatter, and the demand for larger and higher resolution screens. For this reason the design of the screens has been modified and, in correspondence, the light source is getting closer to the panel LCD, with the increased risk of penetrating more light from outside into the peripheral zone of the LCD panel ("blind zone") (see figure 1). This development also increases the shading requirements (darkening) of the double-sided adhesive tape and therefore require new concepts for the preparation of adhesive tapes black

In addition the double-sided adhesive tape must be reflector on the other side.

For this, self-adhesive tapes of double side that on one side have a metal layer and a support black. With these self-adhesive tapes, the reflection of light on one side and absorption on the opposite side, but the presence of non-stick agent in the support layer produces irregularities in the reflective face.

At the same time, to obtain a reflective layer you You can prepare a self-adhesive mass with reflective particles. However, the reflection characteristics that can be achieved They are relatively insufficient.

In JP 2002-350612 patent describe double-sided adhesive tapes for LCD panels, which They have photoprotective properties. The light protection is get with a metallic layer applied on one or both sides of the support sheet, which can also be dyed. Metallization makes the manufacture of adhesive tape and its relatively expensive flatness is insufficient.

In JP patent 2002-023663 double-sided adhesive tapes with properties are also described photoprotectors, for LCD panels. In this case the protection to the light is also obtained with a metallic layer applied on one or both sides of the support sheet.

Patent DE 102 43 215 A describes double-sided adhesive tapes, for liquid crystal displays, with photoabsorbent properties on one side and photoreflective on the other. This patent describes double adhesive tapes black / silver face A transparent or colored support sheet is metallic on one side and dyed black on the other. Thus they get good reflective properties, but the absorption still is insufficient, since the defective parts of the sheet, caused p. ex. by the non-stick agent, they are only covered with the painting and therefore light can pass through these sites (points of needle).

To adhere and make glass screens liquid are still required double-sided self-adhesive tapes that do not have the defects described above or only to a lesser extent.

Thus the present invention aims at provide a double-sided self-adhesive tape that prevents presence of needle points, which on the one hand has the ability to fully absorb light and on the other reflect it better.

This goal is solved with the tapes self-adhesive described in the main claim. In the frame of the present invention it has surprisingly been found that these properties can be achieved with a two-layer self-adhesive mass and the metallization of a PET sheet. The claims subsequent refer to advantageous embodiments of the object of the present invention, as well as the use of the tapes Self-adhesive of the present invention.

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Thus, the main claim concerns to a special self-adhesive tape to make or adhere optical indicators of liquid crystal data (LCDs), which has an upper face and a lower face - with properties photoreflectors on the upper face and photoabsorbents on the face bottom - and also a support sheet with a top face and a lower face, in such a way that the self-adhesive tape is provided on both sides of an external self-adhesive layer, such that between the outer self-adhesive layers there is at least one layer reflective metal to reflect light and at least one layer self-adhesive dyed black to absorb light, and the layer External self-adhesive upper face is transparent.

In a preferred embodiment of the present invention the two outer self-adhesive layers are transparent.

In an advantageous embodiment, the layer reflective metal that is at least between the support sheet and the Self-adhesive layer is located on the upper face.

In another advantageous form of execution there is the minus a reflective metal layer between the support sheet and the layer self-adhesive dyed black. In this case, preferably, the Support sheet becomes transparent or semi-transparent.

In a also preferred embodiment there are at least two reflective metal layers, one between the support sheet and the self-adhesive layer of the upper face, and another between the support sheet and the black-dyed self-adhesive layer. According to an advantageous variant of this embodiment, the support sheet is also transparent or semi-transparent.
parente

Here are some ways to describe advantageous execution of the adhesive tape of the present invention, without trying to limit yourself unnecessarily to the examples chosen.

The self-adhesive layers (d) and (d ') on both faces of the self-adhesive tape of the present invention can be identical or different, especially as to its form (the thickness and other similar characteristics) and its composition chemistry. In an especially preferred embodiment at least the self-adhesive mass on the upper face is transparent of the self-adhesive tape. In accordance with the present invention it can also be advantageous for the self-adhesive masses to be both Self-adhesive tape faces are transparent.

According to a first advantageous embodiment The self-adhesive tape of the present invention is formed by a support sheet layer (a), a reflective metal layer (b), a colored self-adhesive dough (c) and two self-adhesive layers (d) and (d '), of which at least the self-adhesive layer (d) on the face Top is transparent. In this case the reflective metal layer and the colored self-adhesive mass are preferably on sides other than the support sheet. This form of execution is shown in Figure 2.

In another preferred embodiment of the present invention, as depicted in figure 3, the tape double-sided self-adhesive consists of a support sheet (a), two reflective metal layers (b), a colored self-adhesive mass (c) and two self-adhesive layers (d) and (d '). Also the layer Self-adhesive (d) on the upper face is preferably transparent.

In another preferred embodiment of the present invention, according to figure 4, the self-adhesive tape of double side consists of a support sheet (a), a metallic layer reflector (b), a layer of colored self-adhesive mass (c) and two self-adhesive layers (d) and (d '). In this case the metallic layer reflector (b) and the colored self-adhesive dough layer (c) are they are on the same face of the support sheet.

The reflective metal layer (b) is located advantageously between the support sheet, in this case transparent or at least semi-transparent, and the colored self-adhesive dough layer (C). The self-adhesive layer (d) on the upper face is again advantageously transparent.

The following is described below. invention. The indicated limit values should be considered included, that is, contained in the indicated interval.

Preferably the support sheet (a) has a thickness between 5 and 250 µm, more preferably between 8 and 50 µm, especially between 12 and 36 µm, and it's transparent. Layers (b) are metallic-bright and photoreflectors. As a reflective metal layer it is advantageous a silver paint; in another preferred embodiment the sheet (a) is coated on one or both sides with vaporized metal at empty, p. ex. with aluminum or silver. It is also feasible a combination of said finishes (i.e. metal coating vaporized and later painted or vice versa). The thickness of the layers (b) is preferably between 5 and 200 µm.

Layers (c) are self-adhesive masses of color dark, especially black, whose respective thickness is comprised preferably between 5 and 100 µm.

The self-adhesive mass of (c) can be of different chemical nature and can carry various black pigments which advantageously influence the photoabsorbent properties.

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The layers of self-adhesive dough (d) and (d ') have preferably and respectively a thickness between 5 and 250 \ mum. On the double-sided adhesive tape the individual layers (b), (c), (d) and (d ') may have different thicknesses, e.g. ex. the layers Self-adhesive mass (d) and (d ') can be applied with different thicknesses, or each layer, several of them or even all layers can be chosen of the same thickness.

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Support foil

As a support sheet they can be used in principle all polymeric film supports that are transparent. You can use p. ex. polyethylene, polypropylene, polyimide, polyester, polyamide, polymethacrylate, sheets fluorinated polymers, etc. In a way of execution especially preferred polyester sheets are used, especially PET sheets (polyethylene terephthalate). The sheets can be tensioned or they can submit one or more preferred addresses. The directions Preferred are achieved by stretching in one or two directions. In the process of making the sheets, p. ex. PET's are used normally non-stick agents, such as p. ex. silicon dioxide, talc or cretas, zeolites.

Nonstick agents serve to prevent the flat sheets of plastic agglomerate forming blocks due to the effect of pressure and temperature. Usually the Non-stick agents are incorporated into the thermoplastic mixture. Then the particles act as spacers.

Said sheets can be used advantageously for double-sided adhesive tapes of the present invention. But for the self-adhesive tapes of the present invention also You can use sheets that do not carry any non-stick agent or that only contain a very small proportion of them. As an example such sheets include the Hostaphan® 5000 series of Mitsubishi Polyester Film (PET 5211, PET 5333 PET 5210).

Likewise, you should preferably use sheets of Very thin PET, for example 12 µm thick, because they contribute very good technical properties of adhesion to the tape double-sided adhesive, because in this case the sheet is very flexible and can adapt well to the surface roughness of the substrate on which it sticks.

To improve the anchoring of the paint layers the pretreatment of the sheets is very useful, which can consist of a corrosive attack (eg with trichloroacetic acid or trifluoroacetic acid), a corona discharge treatment or with plasma, or in a primer (eg Saran).

In addition, pigments can be advantageously added or coloring particles to the sheet material - especially when it is a transparent or semi-transparent sheet. So, for example, carbon black is suitable for coloring in black and Titanium dioxide particles for coloring on white. Do not However, it is preferable that the diameter of the pigments or particles are less than the final layer thickness of the sheet support. Optimum pigmentations can be achieved with a percentage of 10 to 40% of particles with respect to the material of the sheet.

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Reflective layer (b)

To prepare a highly reflective face, you can apply a silver paint on the sheet (a) or said sheet (a) can be coated on one or both sides with a metal vacuum vaporized, e.g. ex. with aluminum or silver. For the variant from the silver paint a binder matrix is mixed with pigments Silver and / or metal particles. As binder matrix They serve p. ex. polyurethanes or polyesters that have a high refractive index and great transparency. But nevertheless the pigments can also be incorporated into a matrix of polyacrylate or polymethacrylate and then form a coat of paint hardened.

In a very preferred embodiment the layer laminate (a) is coated on both sides with aluminum or silver vaporized under vacuum (sputtering). To obtain excellent reflective properties the spraying process of metal must be controlled so that aluminum or silver remain applied very evenly, in order to achieve optimal reflection (avoiding dispersion effects). Also in a form of execution highly preferred PET sheet is pretreated with plasma before coating it with aluminum or silver. On the one hand, employment of the reflective layer (b) reflects the light and on the other decreases or prevents the transmission of light through the support material. In addition, the surface roughness of the sheet is compensated support.

For the elaboration process it can be advantageously further protect the reflective face with a varnish transparent, before coating it with the self-adhesive dough.

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Self adhesive dough layer (c)

The self-adhesive dough layer (c) can meet various functions In an advantageous embodiment of the present invention layer (c) exerts the function of absorbing light outside essentially completely. Therefore, the transmission of the self-adhesive tape, in this case within a 300-800 nm wavelength range, is preferably <0.5%, more preferably <0.1%, over all <0.01%. According to the present invention this is achieved. advantageously with a layer of black self-adhesive dough.

In a very preferred embodiment of the present invention, carbon black or graphite particles are incorporated into the self-adhesive matrix to color black. When the level of addition is very high (> 20% by weight), in addition to the practically complete absorption of light, an electrical conductivity is achieved, whereby the double-sided self-adhesive tapes of the present invention also possess antistatic properties. As self-adhesive matrix all self-adhesive mass systems known to the specialist can be used. As self-adhesive mass systems are suitable p. ex. the masses of acrylate, natural rubber, synthetic rubber, silicone or EVA. Other self-adhesive masses known to the specialist can also be prepared, such as those cited p. ex. in the "Handbook of Pressure Sensitive Adhesive Technology" [Technology Manual contact adhesives] Donatas Satas (van Nostrand, New York 1989).

For natural rubber adhesive masses this one it is preferably milled to a molecular weight (weight) not less than about 100,000 Daltons, especially not less than 500,000 Dalton, and be additive.

In case of using rubber / synthetic rubber as starting material for the adhesive the possibilities of variation They are wide.

Natural or synthetic rubbers can be used or any mixture of natural and / or synthetic rubbers, being able to basically choose rubber or natural rubbers among all qualities available, for example between crepe, RSS, ADS, TSR or CV, according to the necessary level of purity and viscosity, and the rubber or synthetic rubbers of the group consisting of Styrene-Butadiene Rubbers Statistically copolymerized (SBR), butadiene rubbers (BR), polyisoprenes (IR), butyl rubbers (IIR), rubbers halogenated butyl (XIIR), acrylic rubbers (ACM), ethylene vinyl acetate (EVA) copolymers and polyurethanes and / or mixtures thereof.

Also elastomers can be added thermoplastics to rubbers, in a weight ratio of 10 to 50% by weight with respect to the total elastomer content, to improve the processability. Here it should be noted as examples, especially types of styrene-isoprene-styrene (SIS) and of styrene-butadiene-styrene (SBS), They are especially compatible.

In a preferred embodiment of the present invention preferably self-adhesive masses are used of (meth) acrylate.

Self-adhesive masses of (meth) acrylate used according to the present invention, which can be obtained by radical polymerization, preferably consist of at least 50% by weight of at least one acrylic monomer of the group of Compounds of the following general formula:

one

where the radical R1 = H or CH 3; and the radical R2 is H or CH3 or is chosen from the group of saturated, branched and linear alkyl radicals of 1-30 atoms of carbon.

The monomers are preferably selected such that the resulting polymers can be used as PSAs at room temperature or higher temperatures, especially so that the resulting polymers possess touch'n'close characteristics according to the "Handbook of Pressure Sensitive Adhesive Technology" [Technological Manual adhesives of contact ] by Donatas Satas (van Nostrand, New York 1989).

For the embodiment of the present invention it is especially advantageous that the self-adhesive matrix of (c) is identical to the self-adhesive mass of (d) and (d '). The use of the same self-adhesive mass makes it possible to reinforce the viscoelastic profile of layers (c) and (d) and (d '), thus clearly improving the technical adhesion properties (which is a special advantage over adhesive tapes coated with black paintings or with thick black supports). For self-adhesive acrylate masses this can be achieved by a glass transition temperature T G of the polymers preferably ≤ 25 ° C. To this end, the monomers and the quantitative composition of the monomer mixture are preferably and advantageously chosen so as to obtain the desired TG value for the polymer, according to the Fox equation (G1) (see TG Fox, Bull Am. Phys. Soc. 1 (1956) 123).

2

where n represents the number correlative of the monomers used, w_ {n} the percentage mass of the respective monomer n (% by weight) and T_G, n} the corresponding glass transition temperature of homopolymer of the respective monomer n in K.

Another advantage of the present invention is in which no black dye particle can migrate to the substrate of adhesion, because transparent self-adhesive masses are They are on the outer faces of the self-adhesive tape. This is an important aspect for its relocation, because in the extreme case of a bad glue, when the tape was torn off, black waste would remain on the LCD sheet and the entire piece would be unusable. For the both within the framework of the present invention and in the form of a Especially preferred execution is advantageous that (c) and (d) or (d ') have the same self-adhesive matrix.

Another advantage of owning the same matrix Self-adhesive is that dyes or pigment particles they have less tendency to migrate to the layers of adhesive mass (d) and (d '). Thus there is no risk that the coloring particles, due p. ex. at a different polarity, be more soluble in a matrix and migrate to it.

In addition the double layer structure allows Implement additional functions. So for example in layer (c) swelling agents can also be incorporated, which then improve the vibratory characteristics, or other charges that can reduce The manufacturing price of the adhesive tape without adhesion of the self-adhesive layer (d) or (d ') is affected.

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Self-adhesive masses (d) and (d ')

In a preferred embodiment, the self-adhesive masses (d) and (d ') on both sides of the self-adhesive tape are identical. But according to a special embodiment, it can also be advantageous if the self-adhesive masses (d) and (d ') differ from one another, especially in terms of their layer thickness and / or chemical composition. This way you can regulate p. ex. Different characteristics of stickiness. As self-adhesive dough systems for the double-sided self-adhesive tape of the present invention, acrylate, natural rubber, synthetic rubber, silicone or EVA adhesives are preferably used. In the event that the double-sided self-adhesive tape of the present invention has great reflection, at least on one side, the self-adhesive mass of at least this side preferably has high transparency. Other self-adhesive masses known to the specialist can also be prepared, such as those cited p. ex. in the "Handbook of Pressure Sensitive Adhesive Technology" [Technology Manual contact adhesives] Donatas Satas (van Nostrand, New York 1989).

For natural rubber adhesive masses this one it is preferably milled to a molecular weight (weight) not less than about 100,000 Daltons, especially not less than 500,000 Dalton, and be additive.

In case of using rubber / synthetic rubber as starting material for the adhesive the possibilities of variation They are wide.

You can use natural or synthetic rubbers or any mixture of natural and / or synthetic rubbers, being able to choose basically rubber or natural rubbers from among all the available qualities, for example between crepe, RSS, ADS, TSR or CV types, depending on the necessary level of purity and viscosity, and the rubber or synthetic rubbers of the group consisting of statistically copolymerized styrene-butadiene rubbers (SBR), butadiene rubbers (BR), polyisoprenes (IR), butyl rubbers ( IIR), halogenated butyl rubbers (XIIR), acrylic rubbers (ACM), ethylene-vinyl acetate (EVA) copolymers and polyurethanes and / or their
mixtures

Also elastomers can be added thermoplastics to rubbers, in a weight ratio of 10 to 50% by weight with respect to the total elastomer content, to improve the processability. Here it should be noted as examples, especially types of styrene-isoprene-styrene (SIS) and of styrene-butadiene-styrene (SBS), They are especially compatible.

In a preferred embodiment of the present invention preferably self-adhesive masses are used of (meth) acrylate.

Self-adhesive masses of (meth) acrylate used according to the present invention, which can be obtained by radical polymerization, preferably consist of at least 50% by weight of at least one acrylic monomer of the group of Compounds of the following general formula:

3

where the radical R1 = H or CH 3; and the radical R2 is H or CH3 or is chosen from the group of saturated, branched and linear alkyl radicals of 1 - 30 atoms of carbon.

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The monomers are preferably selected such that the resulting polymers can be used as PSAs at room temperature or higher temperatures, especially so that the resulting polymers possess touch'n'close characteristics according to the "Handbook of Pressure Sensitive Adhesive Technology" [Technological Manual adhesives of contact ] by Donatas Satas (van Nostrand, New York 1989).

In another form of execution of this invention the composition of the comonomers is chosen in such a way that self-adhesive masses can be used as adhesives heat activated.

The polymers can preferably be obtained by polymerization of a monomer mixture composed of esters of acrylic and / or methacrylic acid and / or their free acids, of formula CH2 = CH (R1) (COOR2), in which R 1 = H or CH 3 and R 2 is an alkyl chain of 1-20 atoms of C or H.

The value of the molecular masses M_ {w} (weights) of the polyacrylates used is preferably ≥ 200,000 g / mol.

Very preferably monomers are used acrylics or methacrylics consisting of esters of acrylic acid and methacrylic with alkyl groups of 4 to 14 C atoms, preferably from 4 to 9 C atoms. As concrete examples It is possible to mention, without pretending to adhere to this enumeration, acrylate of methyl, methyl methacrylate, ethyl acrylate, acrylate n-butyl, n-butyl methacrylate, n-pentyl acrylate, acrylate n-hexyl, n-heptyl acrylate, n-octyl acrylate, methacrylate n-octyl, n-nonyl acrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate and its branched isomers, such as p. ex. isobutyl acrylate, 2-ethylhexyl acrylate, methacrylate 2-ethylhexyl, isooctyl acrylate, methacrylate isooctyl

Another type of usable compounds are the bridged cycloalkylalcohol acrylates and methacrylates of 6 At least C atoms. Cycloalkylalcohols can also be substituted, p. ex. with C 1-6 alkyl groups, halogen atoms or cyano groups. As specific examples it is possible mention cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate and acrylate 3,5-dimethylamantyl.

In an advantageous procedure they are used monomers that carry polar groups such as carboxyl radicals, groups  of sulfonic and phosphonic acid, hydroxyl radicals, lactam and lactone, N-substituted amido, amino N-substituted, carbamate, epoxy, thiol, alkoxy, cyano, ether or the like.

Moderately basic monomers are p. ex. N, N-dialkyl substituted amides as p. ex. N, N-dimethylacrylamide, N, N-dimethylmethylmethacrylamide, N-tert-butylacrylamide, N-vinyl pyrrolidone, N-vinyl lactam, dimethylaminoethylmethacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethyl aminoethyl acrylate, N-methylolmethacrylamide, N- (butoxymethyl) -methacrylamide, N-methylolacrylamide, N- (ethoxymethyl) acrylamide, N-isopropylacrylamide, although this relationship should not Be considered exclusive.

Other preferred examples are acrylate of hydroxyethyl, hydroxypropyl acrylate, methacrylate hydroxyethyl, hydroxypropyl methacrylate, allylalcohol, anhydride maleic, itaconic anhydride, itaconic acid, methacrylate glyceridyl, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-Butoxy ethyl methacrylate, acrylate 2-Butoxyethyl, cyanoethyl methacrylate, acrylate cyanoethyl, glyceryl methacrylate, methacrylate 6-hydroxyhexyl, vinylacetic acid, acrylate tetrahydrofuryl acid β-acryloyloxypropionic, trichloroacrylic acid, fumaric acid, crotonic acid, acid aconitic, dimethylacrylic acid, but this relationship should not Be considered exclusive.

According to another very preferred procedure, they use vinyl esters, vinyl ethers as monomers, vinyl halides, vinylidene halides, compounds vinyl with aromatic cycles and heterocycles in position α. Here it is also possible to mention in a non-exclusive way some examples: vinyl acetate, vinylformamide, vinyl pyridine, ethyl vinyl ether, vinyl chloride, vinylidene chloride and acrylonitrile

In addition, photo-initiators with a copolymerizable double bond are used in an advantageous process. Suitable photo-initiators are those of the Norrish-I and II type. Examples include p. ex. benzoin acrylate and an acrylated benzophenone from UCB (Ebecryl P 36®). In principle, all known photoinitiators of the specialist can be copolymerized, capable of crosslinking the polymer by means of a radical mechanism under UV radiation. A summary of possible useful photoinitiators are offered, that can be functionalized with a double, the Hanser Verlag, Munich 1995, Fouassier: "Photoinitiation, Photopolymerization and Photocuring: Fundamentals and Applications" [fundamentals and applications photoinitiation, photopolymerisation and photocuring] link. Complementing Carroy and others included in "Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints" [Chemistry and Technology of UV formulations and EB for coatings, inks and paints], Oldring (editor), 1994, SITA, London.

In another preferred procedure, at described comonomers, monomers are added that have a high statistical glass transition temperature. As components are suitable aromatic vinyl compounds, such as e.g. ex. he styrene, whose cores are preferably from C4 to C 18 and can also carry heteroatoms. As examples especially preferred mention 4-vinylpyridine, N-vinyl phthalimide, methylstyrene, 3,4-dimethoxystyrene acid 4-vinylbenzoic acid, benzyl acrylate, methacrylate benzyl, phenyl acrylate, phenyl methacrylate, acrylate t-butylphenyl methacrylate t-butylphenyl, acrylate and methacrylate 4-biphenyl, acrylate and methacrylate 2-naphthyl and mixtures of these monomers, not due Consider this enumeration as exclusive.

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With the increase in the proportion of aromatics the refractive index of the self-adhesive mass increases and minimizes the dispersion between the LCD glass and the self-adhesive mass, due p. ex. in strange light.

In a later development, resins can be mixed with the self-adhesive masses. As tachyifying resins, all adherent resins known and described in the literature can be used without exception. Examples include pinene, indene and rosin resins, their disproportionate, hydrogenated, polymerized, esterified derivatives and salts thereof, aliphatic and aromatic hydrocarbon resins, terpenic and terpenophenolic resins, as well as C5, C9 and other resins hydrocarbon resins Any combination of these and other resins can be used to tailor the properties of the resulting adhesive mass. In general, all compatible (soluble) resins with the corresponding polyacrylate can be used, especially all aliphatic, aromatic, alkylaromatic hydrocarbon resins, hydrocarbon resins based on pure monomers, hydrogenated hydrocarbon resins, functional hydrocarbon resins and Natural resins It is explicitly refer to the description of the technical condition contained in the "Handbook of Pressure Sensitive Adhesive Technology" [Technology Manual contact adhesives] Donatas Satas (van Nostrand, 1989).

In this case, to improve transparency transparent resins are also preferably used and very compatible with the polymer. Hydrogenated or partially resins Hydrogenated usually have these characteristics.

They can also be added optionally plasticizers, other fillers (such as fibers, carbon black, zinc oxide), crete, solid or hollow glass spheres, microspheres of other materials, silica, silicates), agents nucleating, electrically conductive materials such as p. ex. conjugated polymers, gifted conjugated polymers, pigments metallic, metallic particles, graphite, etc., swelling agents, mixing aids and / or antioxidants, e.g. ex. in form of primary and secondary antioxidants or in the form of agents photoprotectors

In another useful embodiment of this invention the self-adhesive mass (d ') applied on the black layer (c) Contains photoabsorbent particles, e.g. ex. black pigments or carbon black or graphite particles as charge.

You can also add crosslinkers and crosslinking promoters. Crosslinkers suitable for cross-linking by electronic radiation and by UV radiation are by example bi or multifunctional acrylates, bi isocyanates or multifunctional (also in blocked form) or bi or epoxides multifunctional In addition crosslinkers can be added thermo-activatable, such as p. ex. Lewis acids, metal chelates or multifunctional isocyanates.

For optional crosslinking with UV light they can add to the self-adhesive masses absorbent photoinitiators of UV Photoinitiators suitable for this purpose are benzoin ethers, as p. ex. benzoinmethyl ether and benzoinisopropylether; acetophenones substituted, such as p. ex. 2,2-diethoxyacetophenone (which sells the Ciba Geigy® as Irgacure 651®), 2,2-dimethoxy-2-phenyl-1-phenylethanone, dimethoxyhydroxyacetophenone; α-ketoles substituted, such as p. ex. the 2-methoxy-2-hydroxypropiophenone; aromatic sulfonyl chlorides, such as p. ex. the chloride of 2-naphthylsulfonyl, and photoactive oximes such as p. ex. the 1-phenyl-1,2-propanedion-2- (O-ethoxycarbonyl) oxime.

The above-mentioned and other usable photoinitiators, as well as those of the Norrish-I or Norrish-II type, may contain the following radicals: benzophenone, acetophenone, benzyl, benzoin, hydroxyalkylphenyl, phenylcyclohexyl ketone, anthraquinone, trimethylbenzoylphosphinoxide, methylthiobenzenebenzene benzenethiobenzenebenzenebenzene benzene , thioxanthone, hexaarylbis-imidazole, triazine or fluorenone, which may additionally be substituted with one or more halogen atoms and / or one or more alkyloxy groups and / or one or several amino or hydroxyl groups. Fouassier: "Photoinitiation, Photopolymerization and Photocuring: Fundamentals and Applications" [ Photo-initiation, light curing and photo curing: fundamentals and applications ], from Hanser, Munich 1995, a representative summary is offered. Complementing is available Carroy et al in "Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints" [Chemistry and Technology of UV formulations and EB for coatings, inks and paints], Oldring (editor), 1994, SITA, London.

Process of making acrylic self-adhesive masses

For the polymerization the monomers are chosen such that the resulting polymers can be used as PSAs at room temperature or higher temperatures, especially so that the resulting polymers possess touch'n'close characteristics according to the "Handbook of Pressure Sensitive Adhesive Technology" [Technological Manual contact adhesives ] by Donatas Satas (van Nostrand, New York 1989).

In order to ensure that the self-adhesive masses have a glass transition temperature T G preferably ≤ 25 ° C, according to the above, the monomers and the quantitative composition of the monomer mixture are preferably and advantageously chosen so that the value T G is obtained. } desired for the polymer, according to the Fox equation (G1) (see TG Fox, Bull. Am. Phys. Soc. 1 (1956) 123).

4

where n represents the number correlative of the monomers used, w_ {n} the percentage mass of the respective monomer n (% by weight) and T_G, n} the corresponding glass transition temperature of homopolymer of the respective monomer n in K.

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Self-adhesive poly (meth) acrylate masses are advantageously prepared by conventional radical polymerizations. In radical propagation polymerizations, initiation systems are preferably used which also contain other polymerization initiators, especially those of the azoic or peroxy type, which thermally decompose radicals. But in principle all acrylate initiators used and known by the specialist serve. The production of C-centered radicals is described in Houben Weyl, "Methoden der Organischen Chemie" [ Organic Chemistry Methods ], vol. E 19a, p. 60-147. These methods are preferably used analogously.

Examples of radical sources are peroxides, hydroperoxides and azo compounds. As examples typical, but not exclusive, of radical initiators fits Mention in this case: potassium peroxodisulfate, peroxide dibenzoyl, cumene hydroperoxide, cyclohexanone peroxide, di-tert-butyl peroxide, azodiisobutyronitrile, cyclohexyl sulfonyl acetyl peroxide, diisopropyl percarbonate, tert-butyl peroctoate, benzopinacol. In a very preferred embodiment is used 1,1'-azo-bis- (cyclohexylnitrile) (Vazo 88® from DuPont) or azoisobutyronitrile (AIBN) as radical initiator.

The average weight molecular weights M_ {w} of the self-adhesive masses formed by polymerization radicals are chosen very preferably so that they are in a range of 200,000 to 4,000,000 g / mol; in concrete, for later use as hot melt adhesives electrically conductive, self-adhesive masses are made with average molecular weights M w between 400,000 and 1,400,000 g / mol. The average molecular weight is determined by size exclusion chromatography (GPC) or spectrometry of masses with laser-assisted matrix desorption / ionization (MALDI-MS).

The polymerization can be carried out in bulk, in the presence of one or more organic solvents, in the presence of water or in mixtures of organic solvents and water. It is attempted to use the least possible amount of solvent. Suitable organic solvents are pure alkanes (eg hexane, heptane, octane, isooctane), aromatic hydrocarbons (eg benzene, toluene, xylene), esters (eg ethyl acetate, propyl, butyl or hexyl), halogenated hydrocarbons (eg chlorobenzene), alkanols (eg methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether) and ethers (eg diethyl ether, dibutyl ether) or mixtures thereof. Aqueous polymerization reactions can be carried out in a hydrophilic or water miscible co-solvent, to ensure that the reaction mixture is in the form of a homogeneous phase during the monomer addition. The co-solvents advantageously usable in the present invention are chosen from the following group, consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkyl pyrrol-idinones, N-alkyl pyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and their salts, esters , organosulfides, sulfoxides, sulfones, alcoholic derivatives, hydroxyether derivatives, amino alcohols, ketones and the like, as well as derivatives and mixtures thereof.
same.

The polymerization time is from 2 to 72 hours according to the degree of conversion and the temperature. The older the polymerization temperature can be chosen, that is, how much the greater the thermal stability of the reaction mixture, the lower It will be the resulting reaction time.

When starting the polymerization, the heat input for the thermal decomposition of the initiators. Polymerization can be started by heating to 50-160 ° C, depending on the type of thermally initiator dissociable.

It can also be useful for its preparation polymerize the self-adhesive masses of (meth) acrylate in bulk. In such a case, the use of the technique of prepolymerization The polymerization starts with UV light, but Only up to 10-30% conversion is carried out. This polymer syrup can then be included p. ex. in welded sheets (in the simplest case, in ice cubes), and then polymerize in water to a high degree of conversion. Then these beads can be used as a hot melt adhesive. acrylate, using with special preference in the fusion process laminar materials that are compatible with polyacrylate. In this method of preparation materials can also be added thermally conductive before or after polymerization.

Another useful method to prepare the dough Self-adhesive poly (meth) acrylate is the anionic polymerization. In this case, as a reaction medium preferably use inert solvents, such as p. ex. hydrocarbons aliphatic and cyclo-aliphatic or also aromatic hydrocarbons.

In this case the living polymer is represented generally by the structure P_ {L} (A) -Me, where Me is a group I metal, such as p. ex. lithium, sodium or potassium, and P L (A) is a growing polymer block formed by acrylic monomers. The molar mass of the polymer a prepare is regulated by the concentration ratio of initiator at monomer concentration. As initiators of polymerization are appropriate p. ex. n-propyl lithium, n-butyllithium, sec-butyllithium, 2-naphthyl lithium, cyclohexyl lithium or octyl lithium, although this relationship is not intended to be complete. To polymerize acrylates are also known initiators based on complexes of samarium (Macromolecules, 1995, 28, 7886), which can also be used here.

Initiators can also be used difunctional like the 1,1,4,4-tetraphenyl-1,4-dilithiobutane or the 1,1,4,4-tetra-phenyl-1,4-dilithioisobutane.  Co-coaters can also be used. How coinitiators are suitable, among others, lithium halides, alkoxides of alkali metals or alkylaluminum compounds. In one version highly preferred ligands and coinitiators are selected from such that acrylic monomers, such as p. ex. acrylate of n-butyl and acrylate 2-ethylhexyl, can be directly polymerized, without having to generate them in the polymer by transesterification with the corresponding alcohol.

To prepare self-adhesive masses of poly (meth) acrylate with a narrow distribution of molecular weights are also suitable methods of controlled radical polymerization. Then it is used preferably in the polymerization a control reagent of the General Formula:

5

where R and R1, chosen independently or equally from each other, represent

-

C 1 alkyl radicals up to C 18, C 3 to C 18 alkenyl radicals, radicals C 3 to C 18 alkynyl, branched and linear;

-

C 1 alkoxy radicals up to C 18;

-

C 1 alkyl radicals up to C 18, C 3 to C 18 alkenyl radicals, radicals C 3 to C 18 alkynyl, substituted with at least one group OH or a halogen atom or a silyl ether group;

-

heteroalkyl radicals C 2 -C 18 with at least one O atom and / or a NR * group in the carbon chain, R * being any radical (especially organic);

-

alkyl radicals C 1 -C 18, alkenyl radicals C 3 -C 18, alkynyl radicals C 3 -C 18, substituted with at least one group ester, an amino group, a carbonate group, a cyano group, a group isocyanate and / or an epoxy and / or sulfur group;

-

cycloalkyl radicals C 3 -C 12;

-

aryl or benzyl radicals C 6 -C 18;

-

hydrogen.

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Control reagents of type (I) consist of preferred and more concrete way of the following compounds:

In this case the halogen atoms are preferably F, Cl, Br or I, with more Preference Cl and Br. As alkyl, alkenyl and alkynyl radicals in the different substituents both the linear chains such as branched.

Examples of alkyl radicals of 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, tridecyl, tetradecyl, hexadecyl and octadecyl

Examples of alkenyl radicals of 3 to 18 carbon atoms are propenyl, 2-butenyl, 3-butenyl, isobutenyl, n-2,4-pentadienyl, 3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl, isododecenyl and oil it

Examples of alkynyl radicals of 3 to 18 carbon atoms are propynyl, 2-butynyl, 3-butynyl, n-2-octinyl and n-2-octadecinyl.

Examples of hydroxyl substituted alkyl radicals are hydroxypropyl, hydroxybutyl or hydroxyhexyl.

Examples of alkyl radicals substituted by halogens are dichlorobutyl, monobromobutyl or trichlorohexyl.

A radical C2-C18 heteroalkyl suitable with at least an atom of O in the carbon chain is, for example, -CH 2 -CH 2 -O-CH 2 -CH 3.

As radicals C 3 -C 12 cycloalkyl serve, for example, cyclopropyl, cyclopentyl, cyclohexyl or trimethyl-cyclohexyl.

As radicals C 6 -C 18 aryl serve, for example, phenyl, naphthyl benzyl 4-tert-butylbenzyl, or other phenyls substituted, such as p. ex. ethylbenzene, toluene, xylene, mesitylene, isopropylbenzene, dichlorobenzene or bromotoluene.

The relationships The preceding ones only serve as examples for each group of compounds and They don't want to be exhaustive.

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As control reagents can also be use the following types of compounds

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6

where R2, also regardless of R and R1, it can be chosen from the group above cited for these radicals

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In the conventional "RAFT process" almost always polymerizes only to small degrees of conversion (see WO 98/01478 A1), in order to achieve weight distributions molecular as narrow as possible. But due to the low conversion levels these polymers cannot be used as masses self-adhesive and not, specifically, as adhesives hot melts, since the high proportion of monomers residuals negatively influences the technical properties of adhesion and contaminates the recycled solvent during the process of concentration; also the corresponding self-adhesive tapes they would present a high level of gas evolution. To avoid the inconvenience of low conversions, in a way of especially preferred embodiment, polymerization starts repeatedly.

Another possible method of polymerization controlled radicals are polymerizations regulated by nitroxides In a favorable process, to stabilize the radicals Nitroxides of type (Va) or (Vb) are used:

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7

where R 3, R 4, R 5, R 6, R 7, R 8, R 9 and R 10 independently each other represent the following compounds or atoms:

i)

halogens like p. ex. chlorine, bromine or iodine,

ii)

linear, branched hydrocarbons, cyclic and heterocyclic from 1 to 20 carbon atoms, which they can be saturated, unsaturated or aromatic,

iii)

esters -COOR 11, alkoxides -OR 12 and / or phosphonates -PO (OR 13) 2, in that R 11, R 12 and R 13 represent radicals of the group ii).

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The compounds of the formula (Va) or (Vb) also they can be attached to polymer chains of any kind (mainly, so that at least one of the radicals above cited constitute one of said polymer chains) and therefore can use to form self-adhesive polyacrylate masses.

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As controlled regulators for polymerization compounds of the following are especially preferred kind:

?

2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (PROXYL), 3-carbamoyl-PROXYL, 2,2-dimethyl-4,5-cyclohexyl-PROXYL, 3-oxo-PROXYL, 3-hydroxylimine-PROXYL, 3-aminomethyl-PROXYL, 3-methoxy-PROXYL, 3-t-butyl-PROXYL, 3,4-di-t-butyl-PROXYL

?

2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO), 4-benzoyloxy-TEMPO, 4-methoxy-TEMPO, 4-chloro-TEMPO, 4-hydroxy-TEMPO, 4-oxo-TEMPO, 4-amino-TEMPO, 2,2,6,6-tetraethyl-1-piperidinyloxyl, 2,2,6-trimethyl-6-ethyl-1-piperidinyloxyl

?

N-tert-butyl 1-phenyl-2-methylpropyl nitroxide

?

N-tert-butyl 1- (2-Naphthyl) -2-methylpropyl nitroxide

?

N-tert-butyl 1-diethylphosphono-2,2-dimethylpropyl  nitroxide

?

N-tert-butyl 1-dibenzylphosphono-2,2-dimethylpropyl  nitroxide

?

N- (1-phenyl-2-methylpropyl) -1-diethylphosphono-1-methyl ethyl nitroxide

?

di-tert-butylnitroxide

?

diphenylnitroxide

?

tert-butyl-tert-amyl nitroxide

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Other technical status can be chosen polymerization methods that allow mass production Self-adhesive through alternative processes:

US Patent 4,581,429 A discloses a process of controlled radical polymerization, initiated by a compound of formula R'R''N-O-Y, where Y is a type of free radical capable of polymerizing unsaturated monomers. However, reactions usually have low yields. He concrete problem is the polymerization of acrylates, which gives place to very poor yields and very low molar masses. The WO 98/13392 A1 discloses chain alkoxyamine compounds open, they have a symmetrical replacement pattern. The patent EP 735 052 A1 reveals a process for preparing elastomers thermoplastics with narrow distributions of the molar masses. WO 96/24620 A1 describes a polymerization process by very specific radical compounds, such as p. ex. phosphorous nitroxides based on imidazoline. WO 98/44008 A1 reveals specific nitroxyls based on morpholines, piperazinones and piperazinodiones. Patent DE 199 49 352 A1 refers heterocyclic alkoxyamines as regulators for controlled radical polymerizations. The latest developments suitable for alkoxyamines or respective free nitroxides improve the efficiency in the preparation of polyacrylates.

As an additional polymerization method controlled, to synthesize the self-adhesive masses of polyacrylate Radical polymerization can be advantageously used by atom transfer (ATRP), preferably using as monofunctional or difunctional, secondary halide initiators or tertiary and, to separate the halide or halides, Cu complexes, Ni, Fe, Pd, Pt, Ru, Os, Rh, Co, Ir, Ag or Au (see patents EP 0 824 111 A1; EP 826 698 A1; EP 824 110 A1; EP 841 346 A1; EP 850 957 A1). The different possibilities of the ATRP are described more extensively in patent documents US 5,945,491 A, US 5,854,364 A and US 5,789,487 A.

Coating processes, finishing of the support material

In a preferred embodiment for the processing, the self-adhesive mass is applied on the material support from a solution. To increase the anchoring of the self-adhesive dough there is the option of submitting layers (b) or (c) and (c) 'to a pretreatment. So p. ex. you can make a pretreatment with corona or plasma discharge, you can apply a primer in molten state or in solution, or it can be Perform a corrosive chemical treatment. However in the case concrete of the metal layer should minimize the power of the corona discharge, otherwise the blade has needle points for burns To apply the self-adhesive mass in solution, removes the solvent by heat input, e.g. ex. in a channel of drying, and, if necessary, the crosslinking reaction is initiated.

The polymers described above may also be applied as hot melt systems (i.e., in molten state).  Therefore for the elaboration process it may be necessary Remove the solvent from the self-adhesive mass. For this you can use in principle all known procedures of specialist. A very preferred procedure is the concentration a through an extruder with one or two spindles. Double extruder Spindle can be operated with the same or opposite direction of rotation. The solvent or water is preferably distilled through Several stages of vacuum. It is also heated according to the temperature of solvent distillation. The residual percentages of Solvents are preferably <1%, more preferably < 0.5% and especially <0.2%. The hot melt adhesive works on molten state

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Various application processes can be adopted for hot melt adhesive coating. In an advantageous embodiment, the self-adhesive masses are applied in a cylinder coating process. In the "Handbook of Pressure Sensitive Adhesive Technology" [Technological Manual contact adhesives] Donatas Satas of (van Nostrand, New York 1989) different application processes described cylinders. In another embodiment, the coating is carried out through a nozzle of molten product. In another preferred process it is applied by extrusion. Extrusion coating is preferably performed through a nozzle. The extrusion nozzles used can be of one of the following three types: T-shaped, fishtail or arc nozzle. Each of them is distinguished by the shape of its flow channel. Through the application process the self-adhesive masses can also undergo an orientation.

To obtain the self-adhesive mass of two layers on one face three different processes are preferred:

a) Coextrusion

Layers (c) and (d) are applied simultaneously with a coextrusion nozzle, which allows to extend the masses Self-adhesive in a single stage. This is not a problem especially if the viscosities of the self-adhesive masses (c) and (d) They are comparable.

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b) Successive application based on dissolution

In this case it is first applied to the support the self-adhesive mass (c) in solution and then, making a second extension, the self-adhesive mass (d) also in solution. This process can take place in two stages or in one machine operation, which consists in extending (c) in solution with an application machine, dry it in a short channel and then extend (d), also with an application machine, and then carry out the complete drying in a longer channel.

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c) Simultaneous application based on dissolution

In this case it is applied in solution with a nozzle and two channels, extending both layers (c) and (d) almost to the same time and then drying them simultaneously in one stage.

It may also be necessary to crosslink the masses self-adhesive In a preferred embodiment it is crosslinked thermally, with electronic and / or UV radiation.

To crosslink by UV it is irradiated with light short wavelength ultraviolet in a range of 200 to 400 nm, according to the UV photoinitiator used, especially using high or medium pressure mercury lamps from 80 to 240 W / cm power. The intensity of the radiation is adjusted to the performance quantum of the UV photoinitiator and the degree of crosslinking wanted.

In an advantageous embodiment of the present invention the self-adhesive masses are also crosslinked by electronic radiation. As typical irradiation devices, linear cathode systems, scanning systems and segmented cathode systems can be used, provided that they are electron beam accelerators. In Skelhorne, Electron Beam Processing, in Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints , in Chemistry and UV and EB formulation technology for coatings, inks and paints , Volume 1, 1991, SITA, London, there is a detailed description of the technical status and the most important process parameters. Typical acceleration voltages are in a range between 50 kV and 500 kV, preferably between 80 kV and 300 kV. The radiation doses used vary between 5 and 150 kGy, especially between 20 and 100 kGy. You can also use both cross-linking methods or other procedures that allow you to use high-energy radiation.

The object of the present invention is also the use of double-sided self-adhesive tapes according to this invention for adhering or manufacturing LC screens. For use as self-adhesive tape, double-sided self-adhesive tapes can go covered with one or two sheets or separating papers. In a form of preferred embodiment silicone sheets or papers are used, such as p. ex. parchment paper or papers coated with HPDE or LDPE, which in turn they are provided with a separation layer based on silicones or fluorinated polymers. In a way of execution especially Silicone PET sheets are preferred as coating.

Self-adhesive tapes according to this invention are especially useful for gluing LEDs (light emitting diodes, LED) as a light source with the module LCD

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Examples

The present invention is illustrated below. through examples, without trying to limit itself unnecessarily to selection of them.

The following methods of test.

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Test methods A. Transmission

The transmission was measured in a range of wavelength from 190 to 900 nm using a Uvikon 923 device from the Biotek Kontron company. The measurement was performed at 23 ° C. The absolute transmission is expressed as the value at 550 nm in% with respect at total light absorption (0% transmission = no step of light; 100% transmission = total light step).

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B. Needle points

A very powerful commercial light source (eg a Liesegangtrainer 400 KG type 649 overhead projector, with a 36 V, 400 W halogen lamp) is covered with a mask so that no light can pass through. This mask has a circular opening 5 cm in diameter in the center. The LCD adhesive tape is deposited on this circular opening. Then the number of needle points in the totally dark environment is counted electronically or visually, which can be distinguished as translucent points when the light source is on.
dida

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C. Reflection

The reflection test is carried out according to the DIN 5036 part 3, DIN 5033 part 3 and DIN 5033 part 4. standards measuring device was used a sphere of Ulbricht type LMT (50 cm in diameter) in combination with a digital indicator type LMT Tau- \ rho-Meter. The measures integrals take place with a normalized light source A and photoelement of Si set to V (λ). It was measured in front of a reference sample of glass. The degree of reflection it is expressed in% as a sum of the percentages of directed light and light scattered

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Polymer one

A conventional 200 l reactor for Radical polymerizations were filled with 2400 g of acrylic acid,  64 kg of 2-ethylhexyl acrylate, 6.4 kg of methyl methacrylate and 53.3 kg of acetone / isopropanol (95: 5). After passing nitrogen gas through for 45 minutes, stirring, the reactor was heated to 58 ° C and 40 g of 2,2'-azoisobutyro-nitrile (AIBN). The outside bath was then heated to 75 ° C and the reaction was constantly performed at said external temperature. After 1 h of Reaction 40 g of AIBN were added again. At 5 a.m. and 10 a.m. it was diluted respectively with 15 kg of acetone / isopropanol (95: 5). TO at 6 and 8 h 100 g of dicyclohexylperoxydicarbonate was added (Perkadox 16®, from Akzo) dissolved in 800 g respectively of acetone. After 24 h the reaction was stopped and cooled to room temperature. Before applying the dough, polymer 1 is dilute with isopropanol up to 30% solids. Then you incorporates with 0.3% by heavy stirring of aluminum (III) acetyl acetonate (solution 3% in isopropanol) with respect to polymer 1.

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Smoke black mass 1

Polymer 1 is diluted with benzine in a drum specific boiling range up to 30% solids. TO then, stirring strongly, 8% by weight of black of smoke (Printex® 25, from Degussa AG) and 0.3% by weight acetylacetonate of aluminum (III) (3% solution in isopropanol) referred to, respectively, to polymer 1. The solution is homogenized during 10 minutes with an Ultraturrax shaker.

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Smoke black mass 2

Polymer 1 is diluted with benzine in a drum specific boiling range up to 30% solids. TO then, stirring strongly, 10% by weight of black is added of smoke (Printex® 25, from Degussa AG) and 0.3% by weight of aluminum (III) acetylacetonate (3% solution in isopropanol) referred, respectively, to polymer 1. The solution homogenize for 10 minutes with an Ultraturrax shaker.

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Reticulation

Self-adhesive masses are applied in solution on a silicon PET sheet 75 µm thick (sheet Siliconature separator) and dried in the oven at 100ºC for 10 minutes.

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Foil (vacuum vaporized coating)

A 12 µm PET sheet, extruded without non-stick agents, from Mitsubishi (Hostaphan® 5210) coated on one or both sides with vacuum vaporized aluminum, until leaving a layer of aluminum on the entire surface. The blade it was coated in a width of 300 mm by the spray method cathodic In this case, ionized argon gas is introduced with charge positive in a high vacuum chamber. Charged ions collide then with a negatively charged Al plate, detaching aluminum particles at the molecular level, which are deposited immediately on the polyester film conducted above the plate.

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Example 1 Black / silver

On one side of the sheet (based on Hostaphan® 5210), coated on both sides with Steamed Al empty, first a layer of carbon black mass 1 is applied in solution and dried at 100 ° C for 10 minutes. The weight is 50 g / m2. Then on this layer polymer 1 is applied in solution and Dry at 100 ° C for 10 minutes. The weight of this layer also It is 50 g / m2. A layer is then applied on the opposite face 100 g / m2 of polymer 1 and again dried at 100 ° C for 10 minutes.

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Example 2 Black / silver

On one side of the sheet (based on Hostaphan® 5210), coated on both sides with Steamed Al empty, first a layer of carbon black mass 2 is applied in solution and dried at 100 ° C for 10 minutes. The weight is 50 g / m2. Then on this layer polymer 1 is applied in solution and Dry at 100 ° C for 10 minutes. The weight of this layer also It is 50 g / m2. A layer is then applied on the opposite face 100 g / m2 of polymer 1 and again dried at 100 ° C for 10 minutes.

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Example 3 Black / silver

On the non-metallic side of the sheet (based of Hostaphan® 5210) coated with Vacuum vaporized is applied first a layer of carbon black mass 2 in solution and dried to 100 ° C for 10 minutes. The weight is 50 g / m2. Then about this layer is applied polymer 1 in solution and dried at 100 ° C for 10 minutes. The weight of this layer is also 50 g / m2. On the opposite side (metallic face) a layer of 100 g / m2 of polymer 1 and again dried at 100 ° C for 10 minutes

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Example 4 Black / silver

On the metallic face of the sheet (based on Hosta-phan® 5210) coated with Steamed Al vacuum is first applied a layer of carbon black mass 2 in solution and dried at 100 ° C for 10 minutes. The weight is 50 g / m2. Then on this layer polymer 1 is applied in solution and Dry at 100 ° C for 10 minutes. The weight of this layer also It is 50 g / m2. On the opposite side (non-metallic face) is then apply a 100 g / m2 layer of polymer 1 and again Dry at 100 ° C for 10 minutes.

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Results

Examples 1 to 4 were tested according to the Methods A, B and C. The results are indicated in Table 1.

8

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From the results of table 1 it can be deduced that examples 1 to 4 have excellent properties in terms of optical defects (absence of needle points) and transmission. further by test C it could be shown that examples 1 to 4 not only they have photoabsorbent characteristics but also a reflection very high on the metallic face. In the case of use on LCD it It represents a significant increase in the light efficiency in the channel bright.

Claims (6)

1. Special self-adhesive adhesive tape optical indicators of liquid crystal data (LCDs), which presents an upper face and a lower face, with properties photoreflectors on the upper face and photoabsorbents on the face bottom, and also a support sheet with a top face and a lower face, the self-adhesive tape provided by both faces of an external self-adhesive layer, characterized because

-

the support sheet is transparent,

-

to the less a self-adhesive layer dyed black is provided, to absorb the light, between the outer self-adhesive layers,

-

to the minus the outer self-adhesive layer of the upper face is transparent, and

-

to the less two reflective metal layers are provided, one between the sheet support and the self-adhesive layer of the upper face, and another between the backing sheet and the black-dyed self-adhesive layer.

2. Self-adhesive tape according to claim 1, characterized in that both external self-adhesive layers are transparent. 3. Self-adhesive tape according to at least one of the preceding claims, characterized in that it has the following sequence of layers:

mass transparent self-adhesive (layer d) - reflective metal layer (layer b) - support sheet (layer a) - reflective metal layer (layer b) - self-adhesive dyed black (layer c) - self-adhesive dough (layer d ').

4. Use of a self-adhesive tape according to at least one of the preceding claims for making or adhering Optical indicators of liquid crystal data. 5. Use according to claim 4 for adhering LCD glasses 6. Data indicating device, glass liquid, which has a self-adhesive tape according to at least one of claims 1 to 3.